Human motion can be impaired by a wide variety of diseases that affect nerve, muscle, bone, or blood vessels, such as multiple sclerosis, traumatic brain injury, stroke, osteoarthritis, and diabetes, among others. Typically, an individual's motion is increasingly impaired as the disease becomes more severe. Walking is especially susceptible to impairment, as the nerves and blood vessels to the legs and feet are vulnerable to damage. Further, because walking requires tremendous energy expenditure and complex coordination between multiple body systems.
When motion becomes sufficiently impaired, an individual employs an assistive device to ease (or to enable at all) ambulation. Typically, the frequency and duration at which an assistive device is used depends on the severity of the disease. For example, when the pain of osteoarthritis increases, or when the imbalance of multiple sclerosis exacerbates, the individual increases use of a cane or crutch; and when the disease ebbs again, the individual reduces usage.
The degree to which an individual uses an assistive device in daily life would be clinically valuable, so as to track the severity and course of a disease, and to assess how an individual is responding to treatment over time. However, measuring the frequency or the duration at which an individual uses an assistive device in their home is extremely difficult. Surveys or questionnaires rely on memory and active participation, which require a lot of effort and are not very reliable. Canes or crutches with embedded sensors are bulky, expensive, run out of power, and provide only low-quality, high-noise data. Thus, there is a need for a system that can measure the frequency and duration of use of an assistive device for mobility, such as a cane, without any special requirement for worn devices or special canes, in order to enable monitoring of the health status of an individual who relies on such assistive devices.